This invention relates generally to canister vacuum cleaners and, more particularly, to bagless canister vacuum cleaners.
Bagless vacuum cleaners have become very popular over the last several years. This popularity is due in large part to the ease with which dust and dirt can be removed from such vacuum cleaners. These vacuum cleaners include canister vacuum cleaners. A canister vacuum cleaner is a type of vacuum cleaner that has a lower chassis than a stand-up type of vacuum cleaner. A typical canister vacuum cleaner has a chassis that is about two (2) feet from the ground. In old style cloth bag-containing canister vacuum cleaners, dust and dirt removal is a difficult and awkward process, frequently requiring the user to extend his or her hand into the cloth bag to physically disengage dust clumps. Canister vacuum cleaners using disposable liner bags minimize the problems associated with cloth bags, but the use of such canister vacuum cleaners requires the continuous replenishment and installation of disposable liner bags. (Also, owners of older model disposable liner bag-containing canister vacuum cleaners often find it difficult to locate a source of properly sized replacement liner bags.) Contrary to these problems associated with bag-containing canister vacuum cleaners, dirt and dust vacuumed up using bagless canister vacuum cleaners is conveniently deposited into an easily removable permanent container, from which dust and dirt can be disposed of without the effort associated with cloth bag-containing canister vacuum cleaners and without having to continually purchase and reinstall disposable liner bags.
Bagless canister vacuum cleaners of the prior art, however, have not been fully satisfactory. Most bagless canister vacuum cleaners have not demonstrated the ability to fully disengage dust and dirt from the vacuum air stream. Those prior art bagless canister vacuum cleaners which have been reasonably successful in disengaging dust and dirt from the vacuum air stream have required a high degree of mechanical complexity. Such mechanical complexity has tended to make those prior art bagless canister vacuum cleaners unduly expensive to manufacture and maintain.
Accordingly, there is a need for a bagless canister vacuum cleaner which avoids these problems with the prior art.
The invention satisfies this need. The invention is a bagless canister vacuum cleaner that is (a) a chassis having a housing unit, the housing unit having an air inlet and roller means for moving the canister vacuum cleaner across a flat surface, (b) an air blower disposed within the chassis, (c) a dust reaction and collection unit disposed within the housing unit and (d) duct work for serially connecting in fluid communication the air inlet in the housing unit, the inlet chamber, the outlet chamber and the air blower. The dust extraction and collection unit comprises an enclosed inlet chamber and an enclosed outlet chamber. The inlet chamber is substantially cylindrical with a typical internal diameter between about 130 mm and about 200 mm. The inlet chamber comprises a bottom wall, generally vertical sidewalls, an upper section, a lower section and an air inlet opening. The sidewalls have an interior height, typically between about 200 mm and about 250 mm, and the upper section of the inlet chamber has an air inlet opening through the sidewalls. The enclosed outlet chamber is disposed concentrically within the upper section of the inlet chamber. The outlet chamber has a bottom wall, a top wall and generally vertical sidewalls. The top wall has a top wall opening and the sidewalls have an interior height, typically between about 50 mm and about 100 mm. The sidewalls also have a large plurality of inlet apertures, each inlet aperture, typically defining an area between about 3 mm2 and about 30 mm2. The inlet apertures are disposed in a band around the sidewalls of the outlet chamber, the band typically has a width between about 20 mm and about 50 mm and a median line disposed between about 30 mm and about 50 mm above the bottom wall. The outlet chamber also has an upper section, a lower section and a circular exterior perimeter edge member disposed around the sidewalls in the lower section of the outlet chamber. The exterior edge member has a diameter which is typically between about 10 mm and about 60 mm less than the internal diameter of the inlet chamber.
In one embodiment, the outlet chamber contains at least one filter for filtering out residual dust within the air prior to the air being exhausted from the outlet chamber. In preferred embodiments, the outlet chamber contains at least two separate filters. In more preferred embodiments, an additional filter, most preferably a HEPA filter, is disposed downstream of the blower to remove virtually all remaining traces of entrained dust particles.
The invention has been found to provide a canister vacuum cleaner with all the conveniences of prior art canister vacuum cleaners, but with increased dust removal efficiency and without excessive mechanical complexity and resulting expense of manufacture.